In this work, a novel heterocyclic compounds such as 1H-pyrazole-1- carbothioamide were synthesized by cyclocondensation reaction of chalcone and thiosemicarbazide as nucleophilic substrate in ethanolic NaOH solution. The structures were characterized by FT-IR, 1H-NMR, 13C -NMR. The molecular geometry of the targeted compounds was optimized using DFT studies. The energy of the HOMO & LUMO and Mulliken atomic charges were also calculated. Besides, electrochemical quantities such as chemical hardness and electronegativity were measured and analyzed by the use of HOMO-LUMO. They also exhibited high antibacterial activities.